1. Field of the Invention
This invention relates generally to transistors and, more particularly, this invention relates to a method of fabricating a Schottky barrier field effect transistor.
2. Description of Prior Art
Metal-oxide-silicon field effect transistors (MOSFETs) are well known. Schottky MOSFETs exhibit several advantages over conventional MOSFETs, namely reduced junction depth, lower series resistance (drain to source) and lower contact resistance.
Platinum silicide (PtSi) Schottky MOSFETs have been proposed in the literature by Bell Laboratories researchers. See, for example, C. J. Koeneke et al, "Schottky MOSFET for VLSI" in IEDM 81 (IEEE, Washington, D.C.), December, 1981 at pp. 367-370, and "Lightly Doped Schottky MOSFET", in IEDM 82 (IEEE, Washington, D.C.), December, 1982 at pp. 466-469. In such platinum silicide Schottky MOSFETs, the inversion channel under the gate cannot extend to the source and the drain. Therefore, there is a potential barrier between the channel and source, and between the channel and drain in such MOSFET devices.
In the fabrication of MOSFET devices by prior physical vapor deposition methods (i.e. evaporation or sputtering), it is difficult or impossible to avoid a metal bridge between the gate and the source and/or between the gate and the drain, resulting in irregular I.sub.DS -V.sub.DS characteristics accompanied by undesirable leakage current levels.